Nowadays, a product that is excellent in regard to air resistance has been developed by visualizing the flow of the fluid body around a measuring object.
Generally, in the case that the flow of the fluid body is visualized, a tracer is flown in the fluid body, the tracer which is dispersed along the fluid body is captured as an image, and the image is observed to visualize the flow of the fluid body. For example, a fluorescent microparticle, an oil smoke, and a hydrogen bubble are used as the tracer.
However, by the method in which the tracer is used, when the high-speed fluid body in which a speed of the fluid body is 50 m/s or more is used as the fluid body, the tracer is dispersed at once, and the tracer is hardly recognized as a streamline in an image on which the dispersed state is captured. In the case that the amount of tracer is largely increased, an influence of the large amount of tracer on the flow of the fluid body may not be negligible.
It is also necessary to recover the tracer, which has once dispersed, on a downstream side of the fluid body that has passed around the measuring object.
On the other hand, there are known streamline observation method and device therefor, in which a liquid that generates a smoke by temperature rise is applied to a thin wire traversing a small wind tunnel and the streamline is visualized using the smoke generated by electric heating of the thin wire (Patent Literature 1).
In the streamline observation method and device therefor, the liquid that generates the smoke by the temperature rise is applied to the thin wire traversing the wind tunnel, and the streamline is visualized using the smoke generated by the electric heating of the thin wire. At this point, a thin tube in which long and thin slit-like gaps or micro holes are formed in a tube axis direction is used as the thin wire, and the electric heating of the thin tube is performed while the liquid that generates the smoke is flown in the thin tube.
The long and thin slit-like gaps or the micro holes are formed in the tube axis direction of the thin tube, and the liquid that generates the smoke is flown in the thin tube. Therefore, the liquid evenly penetrates the long and thin slit-like gaps or the micro holes, and uniformly generates smoke by the electric heating.